it's sticking our nose into Syria that got people killed in London
Airpolice
Oh dear, do you really believe that? The rise of Muslim extremism has been a long time coming - the Crusades, the fall of the Byzantine Empire, Palestine, Arab/Israeli War, the fall of the Shah of Iran, Soviet invasion of Afghanistan, Gulf Wars 1 and 2, the rise of Al Qaeda, the Arab Spring and rise of Daesh. If we had gone to Syria or not then Islamic Terrorism would still be around us - plenty of attacks/planned attacks in the UK before Syria.
As ever defence requires a balance of forces and a spectrum of capabilities to react to the unexpected. Who predicted the retaking of the Crimea by Russia or the taking of some Ukranian land? Finally, the Irish and Swedish that you mention rely upon the strength of its neighbouring allies in NATO - however, as nations within are not meeting their 2% GDP then this alliance is weaker than it should be. The UK is only barely meeting its share and it is one of NATO’s biggest spenders outside of the US.
Finally, no F35 then may as well sell off the Blaircraft Carriers. No ‘cats and traps’ means that its a one horse race of what can fly from them...